Book/Report

FZJ-2019-01548

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Bestimmung von Emissionsraten pflanzlicher Kohlenwasserstoffe bei Sonnenblumen in Abhängigkeit von Temperatur, Lichtintensität und Streß, insbesondere von der Belastung mit Ozon

Schuh, G. (Corresponding author)FZJ* ; Wildt, J.FZJ* ; Kley, D.FZJ*

1996
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21689

Report No.: Juel-3261

Abstract: The emissionrates of isoprene, mono- and sesquiterpenes from sunflower ($\textit{Helianthus annuus L. cv. giganteus}$) were determined in an environmental chamber, a continuously stirred tank reactor. $\alpha$-pinene, $\beta$-caryophyllene and two oxygenated compounds (BOVOCs = Biogenie oxygenated volatile organic compounds; not yet identified) were emitted with rates in the range from 2 $\cdot$ 10$^{-16}$ to 4 $\cdot$ 10$^{-15}$ mol$\cdot$cm$^{-2} \cdot$s$^{-1}$ (cm$^{2}$ one sided leaf area) resp. 30 to 600 ng·per g dryweight and hour (ng$\cdot$g(dr)$^{-1} \cdot$h$^{-1}$). The emissionrates of isoprene, sabinene, $\beta$-pinene and limonene were about 1 to 8$\cdot$10$^{-16}$ mol$\cdot$cm$^{-2} \cdot$s$^{-1}$ (15 - 120 ng$\cdot$g(dr)$^{-1} \cdot$h$^{-1}$). The composition of the emitted VOCs showed a characteristical shape for this plant species. The emissionrates of all terpenes increased exponentially with temperature. The rate of increase in emission was about 5 to 40 %$\cdot$K$^{-1}$ and was more rapid than the increase of vapor pressure of the terpenes. Substance specific differences of the rate of increase of the emissionsrates were observed. For all substances the dependence of their emissionrates on temperature increased withincreasing light intensity. Increasing lightflux resulted in an increase of the emissionrates for all substances. The correlation between VOC-emissionrates and lightintensity yielded increases of emissionrates between 1 and 50$\cdot$10$^{-9}$ mol/Einstein. The raise of emission rates with lightflux was dependent on temperature and increased with increasing temperature. During periods without plant stress the emissionrates exhibited a good correlation with the rate of transpiration ($\Theta$(H$_{2}$O)) as weil as with the rate of net photosynthesis ($\Theta$(CO$_{2}$)). Ratios of emitted carbon per assimilated CO$_{2}$ were in the range of 0,002-0,01 % molC(VOC)/molC(CO$_{2}$). Sunflowers emitted higher amounts of terpenes when they were stressed by mechanical, wounding and Ozone treatment as weil as nutrient- or waterdeficiency. The emissionrates increased by a factor of 5 - 300. Exposure with Ozone had an effect on hydrocarbon emissionrates with a delay-time. 3 - 4 h after exposure with 25 - 120 ppb Ozone the emissionrates increased by a factor of 5 - 100. This increase was only observed on the first day of exposure. Nutrient deficiency resulted in an increase of emissionrates by a factor of 10 - 30 during the whole period when stress was hold on over several days. In situations of mechanical, wounding and Ozone stress, substance specific changes in the emissionspectrum were observed. The stress induced increased emissionrates often declined with time in an exponential manner. Values as before stress were reached after 3 - 10 h. A model was developed to explain the observed phenomena. It seems to be necessary to include biosynthesis of terpenes into models explaining biogenie emissions of hydrocarbons. In addition deposition rates of Ozone were measured. The main pathway of Ozone loss in the chamber is caused by the uptake through the stomata of the plants. However, up to 50 % of the Ozone loss must be explained by other pro ces ses indirectly caused by the plants. Reactions of Ozone with the measured VOCs can not explain these high loss rates for Ozone. [...]

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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